1. Field of the Invention
The present invention relates to an apparatus for winding a belt-like member of a small width helically around an outer periphery of, for instance, a rotating body which is rotatable about an axis of rotation and whose radius from the axis of rotation to its outer periphery changes in correspondence with an axial position. This invention relates as well as to a method of feeding such a belt-like member.
2. Description of the Related Art
As a conventional apparatus for winding a belt-like member or a linear material, is disclosed in, for instance, U.S. Pat. No. 4,775,433 is. The apparatus in the patent comprises: a lead screw extending parallel with an axis of rotation of a toroidal constituent member of a tire; a movable base adapted to threadedly engage with the lead screw and move along the lead screw by the rotation of the lead screw; a rotating block adapted to rotate about a vertical axis by means of a torque actuator disposed on the movable base; a tilting plate having a rail slidably fitted in the rotating block, the tilting plate being adapted to tilt over a base surface by receiving a rotating force from the rotating block; a contour block having a rear surface whose profile is identical to a projected configuration of a crown portion of the tire constituent member, the rear surface being in contact with a front surface of the tilting plate without slipping thereon; a lead screw supported by the tilting plate and extending along the tilting plate; a feed roller which is supported by a moving frame threadedly engaging with the lead screw and is adapted to guide the linear material; and a sensor for measuring a distance between the moving frame and the contour block.
In the case where the belt-like member is wound around the tire constituent member in accordance with the prior art arranged as described above, the tire constituent member is rotated around the axis of rotation. At the same time, the lead screw is rotated, and the feed roller for guiding the linear material is moved along the axis of rotation of the tire constituent member. Consequently, the linear material is helically wound around the outer periphery of the tire constituent member. At this time, since the radius of the tire constituent member changes in correspondence with the axial position, the distance between the moving frame and the contour block exceeds a predetermined value due to the movement of the feed roller. Hence, as a signal is transmitted from the sensor to the lead screw, the lead screw is rotated, which in turn causes the movable base to move along the lead screw. At this time, since a rotational force is imparted from the torque actuator to the tilting plate via the moving block, the tilting plate is inclined until it abuts against the rear surface of the contour block, i.e., until it becomes parallel with a tangent to the outer periphery of the tire constituent member. As a result, the feed roller moves by following the outer periphery of the tire constituent member, and feeds the linear material substantially along a normal line of the tire constituent member.
However, such a conventional apparatus for winding a linear material has drawbacks in that the structure is complicated and the manufacturing cost thereof is high.
In addition, as another apparatus for winding a belt-like member and a method of feeding the same, those disclosed in, for instance, Japanese Patent Application Laid-Open No. 88224/1990 are known. In this technique, after a winding start end of a ribbon for a cap ply is sucked by a suction pad connected to a low-pressure source, a piston rod of a fluid cylinder extends to cause the winding start end of the ribbon to be supplied and pressure-fitted to a belt layer on a belt-forming drum.
With this conventional apparatus for winding a belt-like member and a method of feeding the same, although the winding start end of the ribbon is fed to the drum while being sucked by the suction pad, a maximum sucking force using such a suction pad is restricted to a low level by the atmospheric pressure. Hence, there is a problem in that if an external force or the like acts on the belt-like member while the belt-like member is being supplied, the belt-like member deviates from or, in some cases is, removed from the suction pad.